Knives generally and folding knives particularly are well known having been in use in the public for ages. All these prior art knives include common elements. Among these elements are an elongated handle that typically is split into two sides separated from each other to form a spacing. A blade having a working end and a pivot end located in the tang is pivotally disposed at one end of the handle so as to fill the spacing in the handle when in the closed or folded position and when in the open or working position, the knife blade pivots about the end of the handle and extends outwardly. For a spring biased opening folding knife, some form of means is used to retain the blade of the knife recessed in the spacing unless and until either overcome manually or by a mechanism that in either case allows the blade to pivot and move outwardly to attain a working position.
Numerous mechanisms are known in the art for pivoting the knife blade into working position from its recessed or closed position and many use some form of spring means to achieve this pivoting action either alone or with manual assistance. Different forms of such springs have been devised for achieving the desired pivoting action.
For safety reasons it is particularly desirable to retain the blade in a closed recessed position that may or may not be locked in such position. Similarly, when the knife blade is in the open or working position it is completely unacceptable for the blade to prematurely close. Rather the blade when in the open or working position may be locked in that position or be biased against any undesired movement toward closing until it is desired to pivot the blade to its closed or recessed position.
Many prior art knives utilize a spring that may be a metallic leaf spring to provide locking of the blade in open and closed positions such as U.S. Pat. No. 5,706,584 issued to Bernardini.
Another form of a locking device for a foldable knife is disclosed in U.S. Pat. No. 5,692,304 issued to Campbell wherein the leaf spring forms a means for locking the knife as the spring member includes a v-shaped bend to fit into a notch in the tang of the knife.
In the Collins U.S. Pat. No. 5,400,509, a locking mechanism for the knife is provided when in the open position.
The Opinel Patent U.S. Pat. No. 5,153,995 discloses a biasing means for retaining the blade in the open position.
Other patents of various designs include Leatherman U.S. Pat. Nos. 4,888,869, Yamagishi 4,741,106, Friedman et al. 4,535,539, Naifeh 4,190,953.
None of these patents discloses the blade having a rolling cam, an operating spring to provide a force vector capable of resisting the pivoting of the blade from a closed or folded position to an open position and when in open position resisting the pivoting of the blade to a closed or folded position.